Hidrogéis de gelatina de tilápia (Oreochromis niloticus) associados com hidroxiapatita e κ-carragenana: um novo material para aplicações biotecnológicas

Abstract

With the expansion of aquaculture activity, large amounts of fish waste are wasted, generating an undesirable environmental impact. Therefore, new alternatives have emerged aiming at the reuse of this raw material to obtain biomolecules with biotechnological potential, such as gelatin and hydroxyapatite, which are widely used in the area of tissue engineering and regenerative medicine. In addition to fish waste, red algae are also a source of biomolecules with great potential for application in tissue engineering, such as sulfated polysaccharides. Therefore, the objective of this work was to develop hydrogels based on gelatin and hydroxyapatite extracted from Nile tilapia (O. niloticus) skin residues, associated with κ- carrageenan, derived from the algae Hypnea musciformis, and crosslinked with riboflavin and curcumina aiming at application as a bone-reconstructor. Gelatin was characterized by yield, electrophoretic analysis, gel strength, isoelectric point, FTIR and TGA. On the other hand, hydroxyapatite and κ-carrageenan were characterized in terms of FTIR, TGA, SEM-EDS, DR-X and NMR. Five hydrogel formulations were developed: GC; GCH; GCHRib; GCHRibUV and GCHCurc, which were prepared with gelatin, carrageenan, hydroxyapatite and crosslinkers. The hydrogels were characterized by means of FTIR, TGA, DR-X, SEM, SEM-EDS, degree of swelling, degree of cross-linking and cytotoxicity with fibroblasts and osteoblasts. Gelatin had a high molecular weight and a high gel strength (277±20 g). Hydroxyapatite and κ- carrageenan were identified by DR-X and NMR, respectively. On the hydrogels, the FTIR identified the main groups and bonds of the compounds present in the matrix. In TGA, it was possible to confirm that the addition of hydroxyapatite increased the thermal stability. In the SEM it was identified that the hydrogels are porous. The MEV-EDS identified the chemical elements that are part of the composition of the biomolecules used. The hydrogels showed an excellent degree of swelling. In terms of crosslinking, it was confirmed that hydroxyapatite acted as a crosslinker, and that riboflavin and curcumin also showed good results, with greater emphasis on the hydrogel containing curcumin (GCHCurc). Finally, all hydrogels showed cell viability (>100%) in fibroblast and osteoblast cells. Thus, it was possible to conclude that the hydrogels of gelatin, hydroxyapatite and κ-carrageenan cross-linked with riboflavin and curcumin have great potential to be used in the area of bone reconstruction, with greater emphasis on GCHCurc.